In the client-server network architecture of the Internet and/or Web, electronic documents are stored in computer systems running server programs and are accessed by computer systems running client programs. For example, information on the Web is made available by Web servers for access by client programs such as Web browsers (e.g., Netscape's Navigator, Microsoft's Internet Explorer, Java's micro-browser).
Information on the Internet and/or Web may be represented by specially formatted text files (e.g., Web pages) written in Hypertext Markup Language (“HTML”) or some other markup language, such as XML, DHTML, and/or VRML. Each text file may be identified by a network address such as a Universal Resource Locator (“URL”). A typical Web page may include one or more hyperlinks that refer to the network addresses of other Web pages. Hyperlinks may be displayed as underlined text or graphical images that, when clicked, send a request for the associated page. For example, when a hyperlink in a home page is selected, a request is sent out by the client to the address specified in the hyperlink, and the associated Web page is downloaded and displayed, replacing the home page on the user's screen with the associated Web page.
Browsers and other client programs typically use a communications protocol such as Hypertext Transfer Protocol (“HTTP”) to request pages from Web servers. HTTP is a request/response protocol. Through a connection established between a client and a server, the client sends a request to the server, and the server provides a response to the client.
An online service provider (e.g., an Internet service provider (“ISP”)) may be used to provide users with access to the Internet and/or World Wide Web (“Web”). In general, a user relies on an ISP to enable communication over the Internet and/or Web. An ISP may offer services in addition to basic Internet access such as, for example, providing email and instant messaging services enabling electronic communication, Web-hosting services allowing users to publish homepages, newsgroup services allowing users to read and post to newsgroups, and image services allowing users to view and order digital images of pictures from a developed film roll.